1. Field of Invention
The invention relates to an images forming apparatus including an image forming device that ejects ink onto a sheet and a suction-type sheet feed table.
2. Description of Related Art
There exists a serial image forming apparatus that includes an inkjet print head that ejects ink from nozzles thereof onto a sheet in order to form an image on the sheet. The image forming apparatus includes a sheet feed table, such as a platen, that is disposed to face a nozzle surface of the print head. A pair of sheet feeding rollers are disposed upstream and downstream of the sheet feed table in a sheet feeding direction, across the sheet feed table. By driving the upstream and downstream sheet feeding rollers intermittently, the sheet held between the upstream and downstream sheet feeding rollers are fed intermittently little by little or stepwise in the sheet feeding direction (sub scanning direction). This feeding manner is referred to as “step feeding”. Although the sheet is not fed in the sub scanning direction during the intermittent sheet feeding, the print head mounted on a carriage ejects ink, while the carriage is moved in a main scanning direction, onto a sheet supported by the sheet feed table in order to form an image on the sheet by a predetermined area or zone at a time.
As the ink ejected from the print head is attached to the sheet held between the downstream and upstream sheet feeding rollers, the sheet absorbs the moisture, resulting in cockling or an uneven, wavy surface. The uneven, wavy surface of the sheet due to the cockling may cause the surface of the sheet to contact the nozzle surface, leading to a smudged image on the sheet and resulting in a deteriorated image quality. In addition, if the sheet is curled up, especially at a leading end of the sheet before being held by the downstream sheet feeding rollers or at a trailing end of the sheet that has passed through the upstream sheet feeding rollers, the curled leading end or the trailing end of the sheet may contact and slide over the nozzle surface, causing the smudges on the sheet or damage on the print head.
To prevent such situations, an inkjet recording apparatus, as disclosed in Japanese Laid-Open Patent Publication No. 2-286340, includes an air suctioning device and a sheet feed table that communicates with the air suctioning device and is provided on a surface thereof with a plurality of small air intake holes.